Can I modify pre-installed applications on Android?

Hello all. I have an pre-installed application on Android "FM Transmitter" (from ACER manufacturer) and I thought to add a new feature (it's not difficult). My question: Can I access to FM Transmitter files to develop my new feature?


Information about my mobile:

• Brand: ACER
  Model: Z500
  Android Version: 4.4.2

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